Endosperm-specific expression of human acid beta-glucosidase in a waxy rice
1 Transactiva Srl, Via J. Linussio 51, 33100 Udine, Italy
2 Regional Coordination Centre for Rare Diseases, University Hospital S. Maria Misericordia, P.zale S. Maria della Misericordia 15, 33100 Udine, Italy
3 Department of Agriculture and Environmental Sciences, University of Udine, Via delle Scienze 206, 33100, Udine, Italy
Rice 2012, 5:34 doi:10.1186/1939-8433-5-34Published: 6 December 2012
The deficiency of human acid beta-glucosidase (hGCase) causes Gaucher disease, a rare genetically-inherited disorder currently treated by enzyme replacement therapy using recombinant CHO-derived GCase. In an attempt to provide an alternative and more efficient production system, a chimeric cDNA coding for hGCase operatively linked to the signal peptide of rice glutelin 4 (GluB4) was put under the control of the GluB4 endosperm-specific promoter and inserted into the genome of a waxy rice.
Molecular, immunological and biochemical analyses showed that recombinant hGCase, targeted to the protein storage vacuoles of rice endosperm cells, is equivalent to the native protein and has a glycosylation pattern compatible with direct therapeutic use. Compared to a previous study carried out on transgenic tobacco seeds, enzyme contents per unit of biomass were drastically increased; in addition, differently from what observed in tobacco, rice seed viability was unaffected by hGCase even at the highest production level. Transgenic seed polishing combined with a pretreatment of seed flour greatly facilitated hGCase extraction and purification with an industrially-scalable procedure.
This study opens up the possibility to efficiently produce in the rice seed pharmaceutical compounds which are available in limited amounts or completely excluded from clinical practice due to the inadequacy of their production systems.